The present invention is generally directed to toner processes, and more specifically, to processes which utilize aggregation and coalescence, or fusion of latexes, colorant, such as pigment, dye, or mixtures thereof, and optional additive particles. In embodiments, the present invention is directed to processes which provide custom color toner compositions with, for example, a volume average diameter of from about 1 micron to about 25 microns, and more specifically, from about 2 microns to about 12 microns, and a narrow particle size distribution of, for example, about 1.10 to about 1.45 as measured by the Coulter Counter method. The resulting custom color toners can be selected for known electrophotographic imaging and printing processes, including digital color processes.
The present invention in aspects thereof is directed to a process for the preparation of custom toners by mixing a number of polymer encapsulated colorant latex particles, and more specifically, by blending and aggregating a number, such as four, different colorant polymer encapsulated miniemulsion latexes, and wherein each of the miniemulsion latex emulsions is comprised of monomer particles, more specifically submicron in size of from, for example, about 100 nanometers to about 1,000 nanometers, and more specifically, from about 200 nanometers to about 600 nanometers in volume average diameter, a nonionic surfactant and an ionic surfactant of opposite charge polarity to that of the ionic surfactant in the colorant dispersion, heating to accomplish polymerization of the monomer, thereafter heating the resulting mixture at, for example, below about the polymer glass transition temperature, and more specifically, from about 35xc2x0 C. to about 60xc2x0 C. (Centigrade) to form toner sized aggregates of from about 2 microns to about 25 microns in volume average diameter, and which toner is comprised of polymer, colorants, and optional additive particles, followed by heating the aggregate suspension above about the resin, or polymer glass transition temperature, and more specifically, at, for example, from about 70xc2x0 C. to about 100xc2x0 C. to effect coalescence or fusion of the components of the aggregates and to form mechanically stable integral custom toner particles. Each miniemulsion can contain, for example, a latex of water, polymer or resin, and colorant, oil, or monomer, water, surfactants, and more specifically, a cosurfactant, such as an alcohol, an alkane, an ether, an alcohol ester, an amine, a halide, or a carboxylic acid ester, which cosurfactant is more specifically inert, nonvolatile, water insoluble, and is a liquid at a temperature of, for example, from about 40xc2x0 C. to about 90xc2x0 C., and contains a terminal aliphatic hydrocarbyl group with at least about 10 carbon atoms, and more specifically, from about 12 to about 24 carbon atoms, and mixtures thereof, and more specifically, an aliphatic alcohol with at least about 8 carbon atoms, such as from about 10 to about 25 carbon atoms, and an alkane with from about 10 to about 30 carbon atoms. The cosurfactant primarily functions to reduce the diffusion of monomer out of the monomer droplet and enables relatively stable miniemulsions since, it is believed, there is formed intermolecular complexes at the oil/water interface. The complexes are believed to be liquid condensed and electrically charged thus creating a low, for example from about 0.5 dyne/centimeter to about 5 dyne/centimeter interfacial tension and high resistance to droplet coalescence.
With the present invention in embodiments, there is selected colorant encapsulated latexes containing a polymer generated by miniemulsion polymerization process. Aggregation/coalescence of the colorant encapsulated polymer latexes permit, for example, the generation of a wide range of colored toner compositions with, for example, high colorant loading, narrow particle size distribution, and excellent projection efficiency. Other advantages in embodiments include, for example, (1) excellent particle dispersion in the resin matrix; (2) acceptable mechanical properties; (3) protection of the colorant from outside influences during toner processing; (4) protection of the matrix or toner resin from interaction with the colorant; and (5) the generation of custom color toners with uniform triboelectric charging characteristics independent of the colorant present and wherein the colorant is passivated. When the xerographic properties, such as triboelectric charge (tribo), admix, developer stability, humidity sensitivity, and the like of highlight color and black toners, are substantially equivalent, the toners can be considered triboelectrically passivated. One primary main advantage of a blended mixture of two passivated toners is their interchangeability.
Embodiments of the present invention are directed to processes for the preparation of toners, and more specifically, highlight color toners and custom color toners. A highlight color toner can be a single toner of a single color of, for example, a saturated hue, which can be utilized with a second color toner like a black toner. These colored toners may be imaged on documents with twin engine xerographic copiers or printers, where each engine comprises a separate charging, exposure, development, transfer, and cleaning component, one for each color toner, or with a single engine xerographic copier or printer which utilize two separate development stations, one for each color, and where the paper, transparency, or other throughput substrate makes either one or two cycles. An example of a single engine printing/copying device with only one cycle can be referred to as trilevel xerography. Applications for highlight color include, for example, emphasizing important information, headlining titles in documents, slides, overhead transparencies, figures and the like. The image color density of a highlight color may be controlled by the developed toner mass per unit area, for example, the higher the toner mass per unit area, the darker the color. Typical highlight colors are common colors desired by many different types of customers, such as red, blue, brown, green, and the like, and wherein a custom color toner can be a very specific highlight color toner. Often toners with these colors are used for corporate logos, letterhead, government flags, or official document seals, where the color coordinates are specified. Examples of custom colors are Xerox Corporation Blue(copyright), IBM Blue(copyright), Blue CrossBlue(copyright), and the like. Other custom colors may include gold, silver, fluorescent colors, and the like.
The aforementioned toners are especially useful for imaging processes, especially xerographic processes, which usually enable high toner transfer efficiency, such as those having a compact machine design without a cleaner, or those that are designed to provide high quality colored images with excellent image resolution, improved signal-to-noise ratio, and image uniformity.
There is illustrated in U.S. Pat. No. 4,996,127, the disclosure of which is totally incoporated herein by reference, a toner of associated particles of secondary particles comprising primary particles of a polymer having acidic, or basic polar groups and a coloring agent. The polymers selected for the toners of the ""127 patent can be prepared by an emulsion polymerization method, see for example columns 4 and 5 of this patent. In column 7 of this ""127 patent, it is indicated that the toner can be prepared by mixing coloring agent and optional charge additive with an emulsion of the polymer having an acidic or basic polar group obtained by emulsion polymerization. In U.S. Pat. No. 4,983,488, the disclosure of which is totally incoporated herein by reference, there is disclosed a process for the preparation of toners by the polymerization of a polymerizable monomer dispersed by emulsification in the presence of a colorant and/or a magnetic powder to prepare a principal resin component and then effecting coagulation of the resulting polymerization liquid in such a manner that the particles in the liquid after coagulation possess diameters suitable for a toner. It is indicated in column 9 of this patent that coagulated particles of 1 to 100, and particularly 3 to 70, are obtained. In U.S. Pat. No. 4,797,339, the disclosure of which is totally incoporated herein by reference, there is disclosed a process for the preparation of toners by resin emulsion polymerization, wherein similar to the ""127 patent certain polar resins are selected. In U.S. Pat. No. 4,558,108, the disclosure of which is totally incoporated herein by reference, there is disclosed a process for the preparation of a copolymer of styrene and butadiene by specific suspension polymerization.
In U.S. Pat. No. 5,561,025, the disclosure of which is totally incorporated herein by reference, there are illustrated emulsion/aggregation/coalescence processes wherein water phase termination agents, that is chain transfer agents that are not water miscible are selected.
Other prior art that may be of interest includes U.S. Pat. Nos. 3,674,736; 4,137,188 and 5,066,560, the disclosures of which are totally incorporated herein by reference.
Emulsion/aggregation processes for the preparation of toners are illustrated in a number of Xerox patents, the disclosures of each of which are totally incorporated herein by reference, such as U.S. Pat. No. 5,290,654, U.S. Pat. No. 5,278,020, U.S. Pat. No. 5,308,734, U.S. Pat. No. 5,370,963, U.S. Pat. No. 5,344,738, U.S. Pat. No. 5,403,693, U.S. Pat. No. 5,418,108, U.S. Pat. No. 5,364,729, and U.S. Pat. No. 5,346,797; and also of interest may be U.S. Pat. Nos. 5,348,832; 5,405,728; 5,366,841; 5,496,676; 5,527,658; 5,585,215; 5,650,255; and 5,650,256. The appropriate components and processes of these patents may be selected for the processes of the present invention in embodiments thereof.
Processes for the preparation of spherical toners at coalescence temperatures of from about 100xc2x0 C. to about 120xc2x0 C. are illustrated in U.S. Pat. No. 5,501,935, the disclosure of which is totally incorporated herein by reference.
It is a feature of the present invention to provide toner processes with many of the advantages illustrated herein.
In another feature of the present invention there are provided simple and economical processes for the preparation of custom colored toner compositions with excellent colorant, especially pigment dispersions, thus enabling the achievement of excellent color print quality, and wherein there is selected a number, for example from about 2 to about 10, of polymer encapsulated latex colorants.
A further feature of the present invention is to provide a toner with high projection efficiency, such as from about 80 to about 95, and more specifically from about 85 to about 95 percent efficiency as measured by the Match Scan II spectrophotometer available from Milton-Roy, and for use in transparencies.
In another feature of the present invention there are provided emulsion aggregated toners with excellent high intensity color resolutions, and which toners possess high light transmission allowing about 80 to 95 percent of the transmitted light passing through a fused image on a transparency to reach the screen from an overhead projector.
Also, in a further feature of the present invention there is provided a process for the preparation of custom toner compositions with a volume average diameter of from about 1 to about 20 microns, and more specifically from about 2 to about 12 microns, and a particle size distribution of about 1.10 to about 1.35, and more specifically from about 1.15 to about 1.25 as measured by a Coulter Counter without the need to resort to conventional classifications to narrow the toner particle size distribution, and wherein there are selected encapsulated colorants.
Moreover, in another feature of the present invention there are provided simple and economical processes for the direct preparation of a wide range of custom colored toner compositions with, for example, excellent projection efficiency and narrow GSD.
Moreover, in a further feature of the present invention there is provided a process for the preparation of toners which after fixing to paper substrates result in images with gloss values of from about 20 Gardner Gloss Units (GGU) to about 70 GGU as measured by Gardner Gloss meter matching of toner and paper.
In a further feature of the present invention there is provided a process for the preparation of custom color toner by aggregation and coalescence, or fusion (aggregation/coalescence) of latex, colorants, and additive particles, and wherein the latex is a miniemulsion, and there is included therein colorant, a cosurfactant, or a hydrotrope (small water soluble molecules with minimum surface activity), such as sodium xylene sulfonate or sodium toluene sulfonate, which can be selected to enhance latex polymer stability and reduce the amount of undesirable sediment, and wherein there results an encapsulated colorant dispersion that can be aggregated with colorant particles.
In yet another feature of the present invention there are provided custom colored toner compositions with low fusing temperatures of from about 120xc2x0 C. to about 180xc2x0 C., and which toner compositions exhibit excellent blocking characteristics at and above about 45xc2x0 C., and wherein there are selected encapsulated colorants.
It is also a feature of the present invention to provide a process for obtaining highlight or custom color toner compositions which comprises admixing at least two toners generated from colorant encapsulated latexes.
Other features of the present invention include retaining during blending the polymer particle size wherein the blended toners are of the same image resolution as the toners in the primary toner set, and avoiding or minimizing agglomeration of blended toner pigments with each other. Since the toners are isolated as separate toner particles in the primary set of toners thus permitting the blending of small batches of highlight or custom color toners from the primary toner set at low cost. Other advantages of the present invention in embodiments include expanding the range and number of economically feasible highlight or custom color toners; the minimization of toner inventory costs since only the primary blendable toners may need to be stored; the provision of security toners, for example, by including an IR absorbing primary toner in the toner blend; maintaining a primary set of blendable toners for pictorial color toners, highlight and custom color toners, for example a primary set of three color toners (cyan, magenta, and yellow) plus black could be used for pictorial color printing and copying, a highlight set of blended red, blue, brown, and green toners; and the addition of white, unpigmented, fluorescent, metallic, silver, gold or metallic toners to the primary toner set to further increase the range of potential highlight and custom colors available by blending colorant encapsulated passivated toners.
These and other features of the present invention are accomplished in embodiments by the provision of toners and processes thereof. In embodiments of the present invention, there are provided sediment free, or substantially sediment free processes for the preparation of toner compositions by the aggregation/coalescence of latex, colorant and encapsulated colorant, such as pigment particles in the presence of a cosurfactant, and wherein the temperature of the aggregation may be selected to control the aggregate size, and thus the final toner particle size, and the coalescence temperature and time may be utilized to control the toner shape and surface properties, and thereafter blending and mixing can be accomplished utilizing a high shearing device, such as a Brinkman Polytron or IKA homogenizer, at a speed of, for example, from about 3,000 revolutions per minute to about 10,000 revolutions per minute for a duration of, for example, from about 1 minute to about 120 minutes wherein the mixing temperature is from about 20xc2x0 C. to about 5xc2x0 C. below the glass transition temperature of the resin, wherein the temperature below the glass transition temperature is from about 25xc2x0 C. to about 60xc2x0 C., or wherein the coagulant or ionic surfactant is a cationic surfactant, such as dialkylbenzene dialkylammonium chloride like SANIZOL B-50(trademark) available from Kao, or MIRAPOL(trademark) available from Alkaril Chemicals, thereby causing a flocculation or coagulation of the colorant, such as pigment encapsulated latexes, which coagulant can be selected in various effective amounts, such as for example from about 0.1 to about 5 percent, and more specifically from about 0.1 and 2 percent by weight of water; wherein the amount of pigment encapsulated latexes present is from about 1 to about 50 percent, and more specifically, from about 5 and 25 percent by weight of the total dispersion comprising pigment encapsulated latexes and water; wherein the amount of water is from about 50 to about 99 percent, and more specifically, from about 75 and 95 percent by weight of the total dispersion comprising pigment encapsulated latexes and water. Thus, for example, a green custom color toner can be prepared by mixing yellow and cyan pigment encapsulated latexes wherein the yellow pigment encapsulated latex is present in an amount of from, for example, (throughout xe2x80x9cfor examplexe2x80x9d is intended for all ranges) about 40 to about 60 weight percent, and the cyan pigment encapsulated latex is present in an amount of from about 60 to about 40 weight percent based on the total pigment encapsulated latex mixture; an orange custom color toner can be prepared by mixing yellow and magenta pigment encapsulated latexes wherein the yellow pigment encapsulated latex is present in an amount of from about 60 to about 75 weight percent, and the magenta pigment encapsulated latex is present in an amount of from about 40 to about 25 weight percent based on the total pigment encapsulated latex mixture; a red custom color toner can be prepared by mixing yellow and magenta pigment encapsulated latexes wherein the yellow pigment encapsulated latex is present in an amount of from about 35 to about 50 weight percent, and the magenta pigment encapsulated latex is present in an amount of from about 65 to about 50 weight percent based on the total pigment encapsulated latex mixture; a violet custom color toner prepared by mixing cyan and magenta pigment encapsulated latexes wherein the cyan pigment encapsulated latex is present in an amount of from about 55 to about 75 weight percent, and the magenta pigment encapsulated latex is present in an amount of from about 45 to about 25 weight percent, based on the total pigment encapsulated latex mixture; a purple custom color toner prepared by mixing cyan and magenta pigment encapsulated latexes wherein the cyan pigment encapsulated latex is present in an amount of from about 25 to about 40 weight percent, and the magenta pigment encapsulated latex is present in an amount of from about 75 to about 60 weight percent, based on the total pigment encapsulated latex mixture; a brown custom color toner prepared by mixing yellow, magenta and black pigment encapsulated latexes wherein the yellow pigment encapsulated latex is present in an amount of from about 55 to about 75 weight percent, the magenta pigment encapsulated latex is present in an amount of from about 20 to about 30 weight percent, and the black pigment encapsulated latex is present in an amount of from about 5 to about 15 weight percent based on the total pigment encapsulated latex mixture; a lime green custom color toner prepared by mixing yellow, cyan and magenta pigment encapsulated latexes wherein the yellow pigment encapsulated latex is present in an amount of from about 25 to about 40 weight percent, the cyan pigment encapsulated latex is present in an amount of from about 25 to about 40 weight percent, and the magenta pigment encapsulated latex is present in an amount of from about 25 to about 40 weight percent, based on the total pigment encapsulated latex mixture, or there may be mixed a number, such as four, of encapsulated latexes, and wherein each of the latexes contains a polymer shell and a core of a dissimilar colorant, such as black, green, yellow, cyan, magenta, brown, blue, and the like.
Aspects of the present invention relate to a process comprising coalescing a plurality of latex encapsulated colorants and wherein each of the encapsulated colorants are generated by miniemulsion polymerization; a process for the preparation of custom colored toners comprising aggregating and coalescing a plurality of latex encapsulated colorants, and wherein the encapsulated colorants are generated by a miniemulsion polymerization, and wherein the process is accomplished in the presence of a cosurfactant wherein a miniemulsion of the monomer is generated, and wherein each miniemulsion contains, subsequent to polymerization, a colorant core and a polymer shell, and which miniemulsion is generated in the presence of an ionic surfactant, a cosurfactant, and a nonionic surfactant, and wherein the monomer in the miniemulsion is of a diameter of from about 100 to about 1,000 nanometers; and wherein each of the colorants is encapsulated in the polymer generated by the polymerization and optionally wherein the colorant is dissimilar for each of the encapsulated latexes; a process comprising aggregating latexes of polymer encapsulated colorants, and wherein each of the encapsulated colorants are generated by a miniemulsion polymerization; a process wherein the encapsulated colorants are generated by the emulsion polymerization of a colorant and a monomer, wherein a miniemulsion of the monomer is generated, and wherein the miniemulsion contains subsequent to polymerization a colorant core and a polymer shell, and which miniemulsion is generated in the presence of an ionic surfactant, a cosurfactant, and a nonionic surfactant, and wherein the monomer in the miniemulsion is of a diameter of from about 100 to about 1,000 nanometers; and wherein the colorant is encapsulated in the polymer generated by the polymerization; a process wherein the aggregating is accomplished below about the polymer glass transition temperature followed by coalescing, and wherein the coalescing or fusing of the aggregates is accomplished above about the polymer glass transition temperature, and wherein the polymer diameter is from about 200 to about 575 nanometers, and there results a toner with a size of from about 2 to about 30 microns in volume average diameter; a process wherein the temperature below the glass transition temperature is from about 25xc2x0 C. to about 55xc2x0 C., and the heating above the glass transition temperature is from about 60xc2x0 C. to about 100xc2x0 C.; a process wherein the temperature below the polymer glass transition temperature is from about 35xc2x0 C. to about 55xc2x0 C., and the temperature above the polymer glass transition temperature is from about 70xc2x0 C. to about 90xc2x0 C.; a process wherein the temperature at which the aggregation is accomplished controls the size of the aggregates, and wherein the final toner size is from about 2 to about 10 microns in volume average diameter, and wherein the temperature and time of the coalescence or fusion of the components of aggregates control the shape of the resultant toner; a process wherein the aggregation temperature is from about 20xc2x0 C. to about 55xc2x0 C., and wherein the coalescence or fusion temperature is from about 85xc2x0 C. to about 95xc2x0 C.; a process wherein the cosurfactant is an alkane with from about 10 to about 24 carbon atoms, and wherein the alkane is present in an amount of from about 0.05 to about 5 parts, or percent by weight; a process wherein the cosurfactant is an alcohol, or an alkyl thiol; a process wherein the alcohol contains from about 8 to about 20 carbon atoms; a process wherein the alcohol is decanol, lauryl alcohol, tetradecanol, cetyl alcohol, stearyl alcohol, or octadecanol; a process wherein the alcohol is present in an amount of from about 0.1 to about 5 parts, or weight percent; a process wherein the alkane is n-decane, dodecane, tetradecane, hexadecane, octadecane octyne, dodecyl cyclohexane, or hexadecyl benzene; a process wherein the colorant is a pigment, and wherein the pigment dispersion contains an ionic surfactant, and the miniemulsion is a latex containing a nonionic surfactant and an ionic surfactant of opposite charge polarity to that of the ionic surfactant present in a pigment dispersion, and wherein the colorant particles are comprised of pigment particles; a process wherein the surfactant utilized in the colorant dispersion is a cationic surfactant, and the ionic surfactant present in the latex mixture is an anionic surfactant; a process wherein the aggregation is accomplished at a temperature of from about 35xc2x0 C. to about 1xc2x0 C. below the Tg of the latex polymer, or latex resin for a duration of from about 0.5 hour to about 5 hours; a process wherein the coalescence or fusion of the components of aggregates for the formation of integral toner particles comprised of encapsulated colorants is accomplished at a temperature of about 85xc2x0 C. to about 105xc2x0 C. for a duration of from about 1 hour to about 5 hours; a process wherein the polymer shell or coating is selected from the group consisting of poly(styrene-alkyl acrylate), poly(styrene-1,3-diene), poly(styrene-alkyl methacrylate), poly(styrene-alkyl acrylate-acrylic acid), poly(styrene-1,3-diene-acrylic acid), poly(styrene-alkyl methacrylate-acrylic acid), poly(alkyl methacrylate-alkyl acrylate), poly(alkyl methacrylate-aryl acrylate), poly(aryl methacrylate-alkyl acrylate), poly(alkyl methacrylate-acrylic acid), poly(styrene-alkyl acrylate-acrylonitrile-acrylic acid), poly(styrene-1,3-diene-acrylonitrile-acrylic acid), poly(alkyl acrylate-acrylonitrile-acrylic acid), poly(alkyl methacrylate-2-carboxyethyl acrylate), poly(styrene-alkyl acrylate-2-carboxyethyl acrylate), poly(styrene-alkylacrylate-acrylonitrile-2-carboxyethyl acrylate), poly(styrene-1,3-diene-acrylonitrile-2-carboxyethyl acrylate), poly(alkyl acrylate-acrylonitrile-2-carboxyethyl acrylate); and other similar polymers; and wherein the polymer is optionally present in an amount of from about 35 percent by weight to about 99 percent by weight of toner; a process wherein the miniemulsion monomer is a latex, and wherein subsequent to polymerization by heating there results a polymer selected from the group consisting of poly(styrene-butadiene), poly(methylstyrene-butadiene), poly(methyl methacrylate-butadiene), poly(ethyl methacrylate-butadiene), poly(propyl methacrylate-butadiene), poly(butyl methacrylate-butadiene), poly(methyl acrylate-butadiene), poly(ethyl acrylate-butadiene), poly(propyl acrylate-butadiene), poly(butyl acrylate-butadiene), poly(styrene-isoprene), poly(methylstyrene-isoprene), poly(methyl methacrylate-isoprene), poly(ethyl methacrylate-isoprene), poly(propyl methacrylate-isoprene), poly(butyl methacrylate-isoprene), poly(methyl acrylate-isoprene), poly(ethyl acrylate-isoprene), poly(propyl acrylate-isoprene), and poly(butyl acrylate-isoprene); poly(styrene-propyl acrylate), poly(styrene-butyl acrylate), poly(styrene-butadiene-acrylic acid), poly(styrene-butadiene-methacrylic acid), poly(styrene-butadiene-acrylonitrile-acrylic acid), poly(styrene-butyl acrylate-acrylic acid), poly(styrene-butyl acrylate-methacrylic acid), poly(styrene-butyl acrylate-acrylononitrile), poly(styrene-butyl acrylate-acrylononitrile-acrylic acid), poly(styrene-butadiene-2-carboxyethyl acrylate), poly(styrene-butadiene-acrylonitrile-2-carboxyethyl acrylate), poly(styrene-butyl acrylate-2-carboxyethyl acrylate), and poly(styrene-butyl acrylate-acrylononitrile-2-carboxyethyl acrylate); a process wherein the ionic surfactant is an anionic surfactant selected from the group consisting of sodium dodecyl sulfate, sodium dodecylbenzene sulfate, sodium dodecylnaphthalene sulfate, and sodium tetrapropyl diphenyloxide disulfonate, and wherein the colorant core is a dispersion containing a cationic surfactant of a quaternary ammonium salt; a process wherein the encapsulated colorant is carbon black, magnetite, cyan, yellow, magenta, or mixtures thereof; a process wherein the toner particles isolated are from about 2 to about 15 microns in volume average diameter, and the particle size distribution (GSD) thereof is from about 1.15 to about 1.30, wherein each of the surfactants utilized represents from about 0.01 to about 5 weight percent of the total reaction mixture, and wherein there is added to the surface of the formed toner metal salts, metal salts of fatty acids, silicas, metal oxides, or mixtures thereof, each in an amount of from about 0.1 to about 10 weight percent of the obtained toner particles; a process wherein the monomer in the miniemulsion is of a diameter of from about 200 to about 600 nanometers; a process for the preparation of custom color toner which comprises aggregating a number of latex encapsulated colorants containing water, a polymer shell, an ionic surfactant, a cosurfactant, and a nonionic surfactant; coalescing the aggregates generated; and optionally isolating, washing, and drying the toner; a process wherein the isolating washing and drying are accomplished; a process wherein the alkyl thiol selected contains from about 10 to about 18 carbon atoms; a process wherein the alkyl thiol is decanethiol, 1-dodecanethiol, t-dodecanethiol, octadecanethiol, and the like; a process wherein the polymer formed by polymerization of the monomer present in the minimization is poly(styrene-alkyl acrylate-acrylic acid), poly(styrene-1,3-diene-acrylic acid), or poly(styrene-alkyl acrylate-2-carboxyethyl acrylate); a process wherein the polymer is poly(styrene-butyl acrylate-acrylic acid), poly(styrene-butyl acrylate-2-carboxyethyl acrylate), or poly(styrene-butadiene-acrylic acid); a process wherein the cosurfactant is selected from the group consisting of alkanes, hydrocarbyl alcohols, ethers, alkyl thiols, amines, halides, esters, and the like; a process wherein the latex encapsulated colorants are dissimilar; a process comprising aggregating separately prepared encapsulated colorants wherein each colorant is dissimilar and wherein each of the encapsulated colorants are generated by a miniemulsion polymerization, and wherein the polymerization is accomplished in the presence of a cosurfactant; a process wherein the cosurfactant is present in an amount of from about 0.1 to about 10 weight percent; a process wherein the cosurfactant is present in an amount of from about 1 to about 3 weight percent; a process comprising the separate forming of latex emulsions containing a monomer and colorant, polymerizing resulting in an encapsulated colorants, and mixing the encapsulated colorants; a process wherein the latex contains water; a process wherein each of the latex encapsulated colorants are comprised of water, a colorant core and a polymer coating; a process for the preparation of individual colorant encapsulated, completely or about 95 to 100 percent, or incompletely, with polymer comprising the polymerization of monomer in the presence of chain transfer agent, initiators, and colorant, and thereafter mixing the encapsulated colorant with colorant particles.
The colorant encapsulated latex polymer can be prepared by a free radical-initiated aqueous miniemulsion polymerization of a mixture of from about 1 to about 10 monomers, and more specifically from about 2 to about 5 monomers, such as olefinic monomers, free radical initiator, chain transfer agent, surfactant, cosurfactant, and water, wherein the amount of monomers selected is, for example, from about 1 to about 40 weight percent, and the amount of water is from about 59 to about 98 weight percent, based on the total reaction mixture amount; heating at, for example, a temperature of about 45xc2x0 C. to about 90xc2x0 C., wherein the resulting latex polymer possesses, for example, a number average molecular weight of from about 1,000 grams per mole to about 200,000 grams per mole, and a weight average molecular weight of from about 5,000 grams per mole to about 500,000 grams per mole, and a glass temperature of from 40xc2x0 C. to about 120xc2x0 C. The colorants selected may be present in various effective amounts, such as from about 1 to about 25, and more specifically from about 2 to about 14 weight percent based on the total monomer or monomers used to prepare the polymer resin. The free radical initiator is selected in amounts of, for example, from about 0.1 to about 10 weight percent based on the total monomer or monomers used to prepare the polymer resin. Chain transfer agents are selected in amounts of from about 0.5 to about 10 weight percent based on the total monomer or monomers selected to prepare the polymer resin. Surfactants are selected in amounts of from about 0.1 to about 10 weight percent based on the total monomer or monomers selected to prepare the polymer resin. Cosurfactant, when present, is selected in various suitable amounts, such as, for example, from about 0.005 to about 5, and more specifically from about 0.5 to about 3 weight percent, based on the total monomer or monomers used to prepare the polymer resin. The latex polymer emulsion is more specifically comprised of from about 1 to about 40 weight percent of polymer particles, of an average diameter of from about 100 nanometers to about 1,000 nanometers, as measured by light scattering technique on a Coulter N4 Plus Particle Sizer.
With the present invention in embodiments, there are selected individual separate latex colorants encapsulated by a polymer more specifically generated by a semicontinuous, miniemulsion polymerization process, followed by aggregation/coalescence of the colorant encapsulated polymers to enable custom color toners with at least four different colors of cyan, yellow, magenta, and black with uniform tribocharging wherein the difference in tribocharging among the different four color toners is, for example, less than about 10 xcexcC/gram, and more specifically less than about 5 xcexcC/gram, such as from about 1 to about 5.
Further embodiments of the present invention include a process for the preparation of custom color toner comprising
(i) aggregating a number, such as four individual and separate latex polymer encapsulated primary colorants or primary colorant encapsulated polymer miniemulsions containing dissimilar colorants such as yellow, cyan magenta, and black, water, polymer, an ionic surfactant, a cosurfactant, and a nonionic surfactant, with a colorant dispersion;
(ii) coalescing or fusing the aggregates generated; and
(iii) cooling, isolating, washing, and drying the toner, and wherein the monomer in the miniemulsion is of a diameter of from about 100 to about 1,000 nanometers; a process wherein the aggregating is below about the polymer shell glass transition temperature present in the colorant encapsulated latex emulsions, the coalescing or fusing is above about the polymer glass transition temperature, and wherein each of the colorant encapsulated polymer particle diameter is from about 200 to about 600 nanometers, and there results a custom color toner with a size of from about 2 to about 20 microns in volume average diameter; wherein the temperature below the polymer glass transition temperature is from about 25xc2x0 C. to about 55xc2x0 C., and the heating above the glass transition temperature is from about 16xc2x0 C. to about 100xc2x0 C.; a process wherein the temperature below the polymer glass transition temperature is from about 35xc2x0 C. to about 60xc2x0 C., and the heating above the glass transition temperature is from about 65xc2x0 C. to about 95xc2x0 C.; a process wherein the temperature at which the aggregation is accomplished controls the size of the aggregates, and wherein the final toner size is from about 2 to about 12 microns in volume average diameter, and wherein the temperature and time of the coalescence or fusion of the components of aggregates control the shape, such as spherical, of the resultant toner; a process wherein the aggregation temperature is from about 20xc2x0 C. to about 55xc2x0 C., and wherein the coalescence or fusion temperature is from about 75xc2x0 C. to about 97xc2x0 C.; a process wherein the colorant is a pigment or a dye, and wherein the pigment or a dye dispersion contains an ionic surfactant, and the minilatex emulsion contains a nonionic surfactant and an ionic surfactant of opposite charge polarity to that of ionic surfactant present in the pigment or dye dispersion; a process wherein the surfactant utilized in the colorant dispersion is a cationic surfactant, and the ionic surfactant present in the latex mixture is an anionic surfactant; a process wherein the aggregation is accomplished at a temperature of from about 15xc2x0 C. to about 1xc2x0 C. below the Tg of the latex polymer, or latex resin for a duration of from about 0.5 hour to about 4 hours; a process wherein the coalescence or fusion of the components of aggregates for the formation of integral toner particles comprised of colorant, resin and optional known toner additives is accomplished at a temperature of about 85xc2x0 C. to about 105xc2x0 C. for a duration of from about 1 hour to about 5 hours; a process wherein there is formed from the latex monomer a polymer selected, for example, from the group consisting of poly(styrene-alkyl acrylate), poly(styrene-1,3-diene), poly(styrene-alkyl methacrylate), poly(styrene-alkyl acrylate-acrylic acid), poly(styrene-1,3-diene-acrylic acid), poly(styrene-alkyl methacrylate-acrylic acid), poly(styrene-alkyl acrylate-2-carboxyethyl acrylate), poly(styrene-1,3-diene-2-carboxyethyl acrylate), poly(styrene-alkyl methacrylate-2-carboxyethyl acrylate), poly(alkyl methacrylate-alkyl acrylate), poly(alkyl methacrylate-aryl acrylate), poly(aryl methacrylate-alkyl acrylate), poly(alkyl methacrylate-acrylic acid), poly(styrene-alkyl acrylate-acrylonitrile-acrylic acid), poly(styrene-1,3-diene-acrylonitrile-acrylic acid), poly(alkyl acrylate-acrylonitrile-acrylic acid), poly(alkyl methacrylate-2-carboxyethyl acrylate), poly(styrene-alkyl acrylate-acrylonitrile-2-carboxyethyl acrylate), poly(styrene-1,3-diene-acrylonitrile-2-carboxyethyl acrylate), and poly(alkyl acrylate-acrylonitrile-2-carboxyethyl acrylate), and wherein the polymer is present in an amount of from about 35 percent by weight to about 99 percent by weight of toner, and wherein the colorant is a pigment; a process wherein the polymer shell formed by polymerization of the latex monomer is selected from the group consisting of poly(styrene-butadiene), poly(methylstyrene-butadiene), poly(methyl methacrylate-butadiene), poly(ethyl methacrylate-butadiene), poly(propyl methacrylate-butadiene), poly(butyl methacrylate-butadiene), poly(methyl acrylate-butadiene), poly(ethyl acrylate-butadiene), poly(propyl acrylate-butadiene), poly(butyl acrylate-butadiene), poly(styrene-isoprene), poly(methylstyrene-isoprene), poly(methyl methacrylate-isoprene), poly(ethyl methacrylate-isoprene), poly(propyl methacrylate-isoprene), poly(butyl methacrylate-isoprene), poly(methyl acrylate-isoprene), poly(ethyl acrylate-isoprene), poly(propyl acrylate-isoprene), and poly(butyl acrylate-isoprene); poly(styrene-propyl acrylate), poly(styrene-butyl acrylate), poly(styrene-butadiene-acrylic acid), poly(styrene-butadiene-methacrylic acid), poly(styrene-butadiene-acrylonitrile-acrylic acid), poly(styrene-butyl acrylate-acrylic acid), poly(styrene-butyl acrylate-methacrylic acid), poly(styrene-butyl acrylate-acrylononitrile), poly(styrene-butyl acrylate-acrylononitrile-acrylic acid), poly(styrene-butadiene-2-carboxyethyl acrylate), poly(styrene-butadiene-acrylonitrile-2-carboxyethyl acrylate), poly(styrene-butyl acrylate-2-carboxyethyl acrylate), poly(styrene-butyl acrylate-acrylononitrile-2-carboxyethyl acrylate), and the like, and wherein the polymer is present in an amount of from 65 percent by weight to about 95 percent by weight of toner, and wherein the colorant is a pigment; a process wherein the anionic surfactant is selected from the group consisting of sodium dodecyl sulfate, sodium dodecylbenzene sulfate, sodium dodecylnaphthalene sulfate, and sodium tetrapropyl diphenyloxide disulfonate, and wherein the colorant dispersion contains a cationic surfactant; a process wherein the colorant is carbon black, magnetite, cyan, yellow, magenta, and mixtures thereof; a process wherein the toner particles isolated are from about 2 to about 15 microns in volume average diameter, and the particle size distribution thereof is from about 1.15 to about 1.30, wherein each of the surfactants utilized represents from about 0.01 to about 10 weight percent of the total reaction mixture, and wherein there is added to the surface of the formed toner metal salts, metal salts of fatty acids, silicas, metal oxides, coated silicas, or mixtures thereof, each in an amount of from about 0.1 to about 10, and more specifically from about 1 to about 3 weight percent of the obtained toner particles; a process wherein the polymer in the miniemulsion is of a diameter of from about 100 to about 1,000 nanometers, or wherein the polymer in the miniemulsion is of a diameter of from about 200 to about 600 nanometers; and a process for the preparation of toner which comprises aggregating individual encapsulated colorant miniemulsions, each containing water, a different colorant, polymer particles of, for example, a diameter of from about 100 to about 1,000 nanometers, an ionic surfactant, a cosurfactant, and a nonionic surfactant; and coalescing the aggregates generated.
With further respect to the present invention, there are generated encapsulated colorant particles by semicontinuous miniemulsion polymerization processes as illustrated herein, and wherein the mixing thereof of a number of individual encapsulated colorants are accomplished by heating to form latex aggregates of polymer encapsulated colorant particles, followed by coalescence to enable custom color toners with a high colorant loading of, for example, from about 10 to about 65, and more specifically from about 15 to about 45 percent by weight of the toner, and wherein the toner particles can be considered fine, that is for example, from about 2 to about 10 microns in volume average diameter.
In embodiments thereof, the present invention relates to a direct custom color toner process comprised of blending a number, such as from about 2 to about 10, of aqueous latex colorant dispersions, each containing, for example, monomer, a different pigment like cyan, magenta, yellow, green, and the like, such as HELIOGEN BLUE(trademark) or HOSTAPERM PINK(trademark), and a cationic surfactant, such as benzalkonium chloride (SANIZOL B-50(trademark)), and wherein the latex miniemulsion contains an anionic surfactant, such as sodium dodecylbenzene sulfonate (for example NEOGEN R(trademark) or NEOGEN SC(trademark)), sodium tetrapropyl diphenyloxide disulfonate (for example DOWFAX 2A1(trademark)) and cosurfactant, and wherein the latex polymer is derived from emulsion polymerization of the monomer selected, such as for example, styrene, acrylates, methacrylates, acrylonitrile, butadiene, acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, and the like; mixing with heating to form a polymer shell encapsulating a colorant core, which on further stirring at a temperature of from about 35xc2x0 C. to about 60xc2x0 C., results in the formation of toner sized aggregates having an aggregate size of from about 2 microns to about 20 microns in volume average diameter as measured by the Coulter Counter (Microsizer II), and a particle size distribution of about 1.15 to about 1.35; thereafter, heating the aggregate suspension at from about 70xc2x0 C. to about 95xc2x0 C. to form toner particles; followed by filtration, washing, and drying in an oven, or the like, and then mixing each of the toners formed and processes for the preparation of toner compositions which comprise blending aqueous encapsulated latex colorant dispersion more specifically containing a pigment, such as carbon black, phthalocyanine, quinacridone or RHODAMINE B(trademark) type red, green, brown, and the like with a cationic surfactant, such as benzalkonium chloride, wherein the latex is a minilatex emulsion derived from the emulsion polymerization of monomers selected from the group consisting of styrene, butadiene, acrylates, methacrylates, acrylonitrile, acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, and the like, and which latex contains an anionic surfactant, such as sodium dodecylbenzene sulfonate or sodium tetrapropyl diphenyloxide disulfonate, a nonionic surfactant, and a cosurfactant, and which colorant encapsulated latex resin size is, for example, from about 100 to about 1,000 nanometers, and more specifically, from about 200 to about 600 nanometers as measured by light scattering technique on a Coulter N4 Plus Particle Sizer; heating the resulting flocculent mixture at a temperature below or about equal to the Tg of the polymer or resin formed in the latex, which heating is, for example, from about 30xc2x0 C. to about 65xc2x0 C. for an effective length of time of, for example, about 0.5 hour to about 2 hours to form toner sized aggregates; and subsequently heating the aggregate suspension at a temperature at or above the Tg of the latex polymer, for example from about 60xc2x0 C. to about 100xc2x0 C., to provide toner particles; and finally isolating the toner product by filtration, thereafter washing and drying in an oven, fluid bed dryer, freeze dryer, or spray dryer; whereby toner particles comprised of polymer, or resin, colorants, and optional toner additives can be obtained; each of the toners obtained can then be mixed at high shear, for example, in a polytron wherein the mixing blade speed is from about 5,000 to about 15,000 rpm, to provide a custom color toner; and a process for the preparation of custom color toner comprising
(i) aggregating a latex polymer encapsulated primary colorant or primary colorant encapsulated polymer miniemulsion containing a primary colorant, such as yellow, cyan, magenta, or black, water, polymer, an ionic surfactant, a cosurfactant, and a nonionic surfactant, with a colorant dispersion;
(ii) coalescing or fusing the aggregates generated;
(iii) cooling, isolating, washing, and drying the toner;.
(iv) admixing two or more primary toners from the above primary set using blending methods including, for example, ball milling, propeller type mixers, such as Logie or Lighnin, tumbling mixers and the like, to provide custom color toners, and wherein when blending, there can be selected at least two primary color toners prepared from pigment encapsulated latexes, and up to about 10, in ratios comprising at least 2 percent by weight of each toner, and more specifically at least 5 percent of each toner, and wherein the total amount is about 100 percent. Blending may be accomplished as illustrated herein, including sequentially, master batching, or splitting a large blended batch into two or more portions, some of which may undergo further blending with other toners. Also, with the present invention there is selected in embodiments a colorant encapsulated latex, more specifically, generated by a semicontinuous, miniemulsion polymerization process, followed by aggregation/coalescence of the colorant encapsulated polymer to enable toners with at least four different colors of cyan, yellow, magenta, and black color toners with uniform tribocharging wherein the difference in tribocharging among the different four color toners is, for example, less than about 10 xcexcC/gram, and more specifically, less than about 5 xcexcC/gram, such as from about 1 to about 5.
More specifically, with the present invention in embodiments thereof there is selected a semicontinuous, miniemulsion polymerization process to form latexes of encapsulated colorants. Generally, the process can be referred to as a miniemulsion polymerization, since the primary colorant particles are dispersed in a monomer or mixture of monomers, with polymerization subsequent to the emulsification. The miniemulsion process generates, for example, a water oil monomer emulsion wherein the amount of oil is from about 0.5 to about 80 weight percent, and more specifically, from about 5 to about 75 weight percent, and the amount of water is from about 20 to about 99.5 weight percent, and more specifically, from about 25 to about 95 weight percent, based on the total oil and water mixture. Subsequently, the resulting miniemulsion together with initiator can be continuously added at elevated temperature, for example temperatures of between about 35xc2x0 C. to about 120xc2x0 C., and more specifically, between about 45xc2x0 C. to about 90xc2x0 C. to accomplish the emulsion polymerization. The encapsulation of colorant particles with the miniemulsion polymerization process offers certain advantages over conventional methods such as the direct dispersion of the particles in the oil medium, rather than in the water phase, by using homogenization in the presence of surfactants. Homogenization is selected to provide the shear to generate the miniemulsion with the colorant particles located inside the miniemulsion droplets. The semicontinuous addition of a miniemulsion to a reactor can provide for the excellent stability of the miniemulsion preventing particle coalescence or flocculation among the interactive monomer emulsion droplets, and maintaining particle size in the range of from about 100 to about 1,000 nanometers, and more specifically, from about 200 to about 600 nanometers, and improved latex stability. The amount of colorant being encapsulated within the polymer is, for example, from about 80 to about 98 percent, based on the total amount of colorant selected for the preparation of the colorant encapsulated polymer particles.
Miniemulsions are, for example, relatively stable submicron, for example, about 100 to about 1,000, and more specifically, from about 100 to about 500 nanometer dispersions of oil (monomer) in water prepared by shearing a composition containing monomers, water, initiator, chain transfer agent, surfactant, cosurfactant, and additionally, colorant. A principle involved in the preparation of a stable miniemulsion, which stability can be maintained by using a cosurfactant to prevent or minimize particle coalescence or flocculation among the interactive monomer emulsion droplets, is the introduction of a low molecular weight cosurfactant, for example, the Mw of the cosurfactant is about 5,000, more specifically not more than about 2,000, and still more specifically from about 100 to about 500, and which cosurfactant is a relatively highly water insoluble to the extent that in water it possesses a solubility of less than about 10xe2x88x923 grams, more specifically less than about 10xe2x88x924 grams, and more specifically from about 10xe2x88x926 grams to about 10xe2x88x924 grams per liter of water to substantially retard the diffusion of monomer and colorant out of the emulsion droplet. The cosurfactant can be comprised of, for example, a long chain alcohol or alkane of, for example, more specifically from about 12 to about 24 carbon atoms in length. The cosurfactant primarily functions to reduce the diffusion of monomer out of the monomer droplet, and more specifically, the cosurfactant can function to reduce the monomer diffusion to an extent of about 75 to about 95 percent to then enable relatively stable miniemulsions because, it is believed, of the formation of intermolecular complexes at the oil/water interface. The enhanced stability of miniemulsions is attributed to the formation of intermolecular complexes at the oil/water interface, which is comprised of solidified bilayers of anionic surfactant and cosurfactant separated by water. The macrostructure of the bilayers is comprised of a tortuous network of irregularly shaped aggregates with diameters between, for example, about 5 to about 100 nanometers. The complexes can be considered liquid condensed (the bilayer network separated by water) and the surface charge (zeta-potential) of the miniemulsions is, for example, from about 50 to about 120 mV, and more specifically, from about 60 to about 100 mV, as determined by the PenKem System 3000 Electrophoresis, electrically charged creating a low interfacial tension, for example, from about 0.5 dyne/centimeter to about 5 dyne/centimeter.
The polymer shell can be prepared by emulsion polymerization methods, and the monomers utilized in such processes include styrene, acrylates, methacrylates, butadienes, isoprenes, acrylic acids, methacrylic acids, acrylonitriles, and the like. Known chain transfer agents, for example dodecanethiol, about 0.1 to about 10 percent, or carbon tetrabromide in effective amounts, such as from about 0.1 to about 10 percent, can also be utilized to primarily control the molecular weight properties of the polymer when emulsion polymerization is selected. Other processes of obtaining polymer particles of from, for example, about 0.01 micron to about 5 microns in diameter can be selected, such as polymer microsuspension process, as disclosed in U.S. Pat. No. 3,674,736, the disclosure of which is totally incorporated herein by reference, polymer solution microsuspension process as disclosed in U.S. Pat. No. 5,290,654 the disclosure of which is totally incorporated herein by reference, mechanical grinding processes, or other known processes.
Long chain aliphatic mercaptans, such as dodecyl mercaptan, are commonly used as chain transfer agents to regulate the polymer molecular weight in emulsion polymerization. These surfactants are usually water-insoluble and could be used as hydrophobes to stabilize the miniemulsion droplets against monomer diffusion and colorant leaching. The miniemulsions stabilized with long chain aliphatic mercaptans are thermodynamically stable. These chain transfer agents may also function as cosurfactants.
Examples of ethylenically unsaturated monomers that can be selected for the processes of the present invention include, for example, vinyl aromatic and aliphatic hydrocarbons such as styrene, xcex1-methyl styrene and similar substituted styrenes, vinyl naphthalene, vinyl toluene, divinyl benzene, and vinyl aliphatic hydrocarbons such as 1,3-butadiene, methyl-2-butadiene, 2,3-dimethyl butadiene, cyclopentadiene and dicyclopentadiene as well as ethylenically unsaturated esters, such as acrylic, methacrylic, cinnamic and crotonic and the like, and esters containing fumaric and maleic type unsaturation, and acid olefinic monomers, such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, 2-carboxyethyl acrylate, sodium acrylate, potassium acrylate, and the like. Particularly preferred monomers include, for example, styrene, 1,3-butadiene, isoprene, alkyl(meth)acrylates such as ethyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, acrylonitrile, vinyl acetate, acrylic acid, methacrylic acid, and 2-carboxyethyl acrylate.
Examples of the polymers formed from monomers after polymerization are poly(styrene-butadiene), poly(methylstyrene-butadiene), poly(methyl methacrylate-butadiene), poly(ethyl methacrylate-butadiene), poly(propyl methacrylate-butadiene), poly(butyl methacrylate-butadiene), poly(methyl acrylate-butadiene), poly(ethyl acrylate-butadiene), poly(propyl acrylate-butadiene), poly(butyl acrylate-butadiene), poly(styrene-isoprene), poly(methylstyrene-isoprene), poly(methyl methacrylate-isoprene), poly(ethyl methacrylate-isoprene), poly(propyl methacrylate-isoprene), poly(butyl methacrylate-isoprene), poly(methyl acrylate-isoprene), poly(ethyl acrylate-isoprene), poly(propyl acrylate-isoprene), and poly(butyl acrylate-isoprene); poly(styrene-propyl acrylate), poly(styrene-butyl acrylate), poly(styrene-butadiene-acrylic acid), poly(styrene-butadiene-methacrylic acid), poly(styrene-butadiene-acrylonitrile-acrylic acid), poly(styrene-butyl acrylate-acrylic acid), poly(styrene-butyl acrylate-methacrylic acid), poly(styrene-butyl acrylate-acrylononitrile), and poly(styrene-butyl acrylate-acrylononitrile-acrylic acid), poly(styrene-butadiene-2-carboxyethyl acrylate), poly(styrene-butadiene-acrylonitrile-2-carboxyethyl acrylate), poly(styrene-butyl acrylate-2-carboxyethyl acrylate), and poly(styrene-butyl acrylate-acrylononitrile-2-carboxyethyl acrylate).
The free radical initiator utilized is generally an emulsion type water-soluble initiator, such as a persulfate like potassium, sodium, or ammonium persulfate, or oil-soluble initiators, such as benzyl peroxide, lauroyl peroxide, 2,2xe2x80x2-azobis(isobutyronitrile), or 2,2xe2x80x2-azobis-(2-methylbutyronitrile), or mixtures thereof. The free radical is selected in amounts of, for example, from about 0.1 to about 10 weight percent based on the total monomer or monomers used to prepare the polymer resin. Chain transfer agents selected include, for example, alkylthiol such as 1-dodecanethiol, in an amount of, for example, about 0.5 to about 10 percent on weight, halogenated carbons, such as carbon tetrabromide, about 0.1 to about 10 percent on weight, based on the monomer or monomers used to prepare the polymer resin, or more specifically an alkylthiol.
Cosurfactants include, for example, alkanes, and hydrocarbyl alcohols, ethers, amines, halides and esters, which are for example, inert, nonvolatile, water insoluble, liquids at a temperature of from about 40xc2x0 C. to about 90xc2x0 C., and contain a terminal aliphatic hydrocarbyl group, and mixtures thereof. The terminal aliphatic hydrocarbyl group of, for example, at least about 10, and more specifically, from about 10 to about 20 carbon atoms contained therein may be unsaturated, but is, more specifically, saturated, and branched, but is, more specifically, straight chain. The molecular weight Mw of the cosurfactant is, for example, not more than about 5,000, more specifically, not more than about 2,000, and still more specifically, from about 100 to about 500. Examples of specific cosurfactants include alkanes, such as n-decane, n-tetradecane, n-hexadecane, n-octadecane, eicosane, tetracosane, 1-decene, 1-dodecene, 2-hexadecyne, 2-tetradecyne, 3-octyne, 4-octyne, and 1-tetradecane; alicyclic hydrocarbons, such as dodecyl cyclohexane; aromatic hydrocarbons, such as hexadecyl benzene; alcohols, such as decanol, lauryl alcohol, tetradecanol, cetyl alcohol, octadecanol, eicosanol, 1-heptadecanol and ceryl alcohol; hydrocarbyl alcohol esters of lower molecular weight carboxylic acids, such as cetyl acetate; ethers, such as octyl ether and cetyl ether; amines, such as tetradecyl amine, hexadecyl amine, and octadecyl amine; halides, such as hexadecyl chloride and other chlorinated paraffins; hydrocarbyl carboxylic acid esters of lower molecular weight alcohols, such as methyl, ethyl and isoamyl octanoate, methyl and octyl caprate, ethyl stearate, isopropyl myristate, methyl, isoamyl and butyl oleate, glyceryl tristearate, soybean oil, coconut oil, tallow, laurin, myristin, olein and the like. With the processes of the present invention, cosurfactants as illustrated herein are selected, such as more specifically cosurfactants of dodecane, hexadecane, lauryl alcohol, or cetyl alcohol, and which cosurfactants are selected in various suitable amounts, such as from about 0.005 to about 5, and more specifically, from about 0.5 to about 3 weight percent, or parts based on the monomer, or monomers used to prepare the polymer resin.
Various known colorants, such as pigments, present in the toner in a suitable amount of, for example, from about 1 to about 65 percent by weight of toner, and more specifically, in an amount of from about 2 to about 45 or about 2 to about 20, and in embodiments from about 2 to about 12 percent by weight, that can be selected include carbon black like REGAL 330(copyright); magnetites, such as Mobay magnetites MO8029(trademark), MO8060(trademark); Columbian magnetites; MAPICO BLACKS(trademark) and surface treated magnetites; Pfizer magnetites CB4799(trademark), CB5300(trademark), CB5600(trademark), MCX6369(trademark); Bayer magnetites, BAYFERROX 8600(trademark), 8610(trademark); Northern Pigments magnetites, NP-604(trademark), NP-608(trademark); Magnox magnetites (trademark)B-100(trademark), or (trademark)B-104(trademark); and the like. As colored pigments, there can be selected cyan, magenta, yellow, red, green, brown, blue, or mixtures thereof. Specific examples of pigments include phthalocyanine HELIOGEN BLUE L6900(trademark), D6840(trademark), D7080(trademark), D7020(trademark), PYLAM OIL BLUE(trademark), PYLAM OIL YELLOW(trademark), PIGMENT BLUE 1(trademark) available from Paul Uhlich and Company, Inc., PIGMENT VIOLET 1(trademark), PIGMENT RED 48(trademark), LEMON CHROME YELLOW DCC 1026(trademark), E.D. TOLUIDINE RED(trademark) and BON RED C(trademark) available from Dominion Color Corporation, Ltd., Toronto, Ontario, NOVAPERM YELLOW FGL(trademark), HOSTAPERM PINK E(trademark) from Hoechst, and CINQUASIA MAGENTA(trademark) available from E.I. DuPont de Nemours and Company, and the like. Generally, colored pigments that can be selected are cyan, magenta, red, brown, orange, or yellow pigments, and mixtures thereof. Examples of magentas that may be selected include, for example, 2,9-dimethyl-substituted quinacridone and anthraquinone dye identified in the Color Index as CI 60710, CI Dispersed Red 15, diazo dye identified in the Color Index as CI 26050, CI Solvent Red 19, and the like. Illustrative examples of cyans that may be used include copper tetra(octadecyl sulfonamido)phthalocyanine, x-copper phthalocyanine pigment listed in the Color Index as CI 74160, CI Pigment Blue, and Anthrathrene Blue, identified in the Color Index as CI 69810, Special Blue X-2137, and the like; while illustrative examples of yellows that may be selected are diarylide yellow 3,3-dichlorobenzidene acetoacetanilides, a monoazo pigment identified in the Color Index as CI 12700, CI Solvent Yellow 16, a nitrophenyl amine sulfonamide identified in the Color Index as Foron Yellow SE/GLN, CI Dispersed Yellow 33 2,5-dimethoxy-4-sulfonanilide phenylazo-4xe2x80x2-chloro-2,5-dimethoxy acetoacetanilide, and Permanent Yellow FGL. Colored magnetites, such as mixtures of MAPICO BLACK(trademark), and cyan components may also be selected as pigments with the process of the present invention. Colorants include pigment, dye, mixtures of pigment and dyes, mixtures of pigments, mixtures of dyes, and the like. More specifically, pigment examples include Pigment Blue 15:3 having a Color Index Constitution Number of 74610, magenta pigment Red 81:3 having a Color Index Constitution Number of 45160:3, Yellow 17 having a Color Index Constitution Number of 21105, carbon black, and food dyes or other known suitable dyes. The colorants, pigment, dye or mixtures thereof selected are present in various effective amounts, such as from about 1 to about 65, and more specifically, from about 2 to about 45 weight percent of the toner.
Surfactants in effective amounts of, for example, 0.01 to about 15 weight percent of the reaction mixture in embodiments include, for example, nonionic surfactants, such as dialkylphenoxypoly(ethyleneoxy)ethanol, available from Rhone-Poulenac as IGEPAL CA-210(trademark), IGEPAL CA-520(trademark), IGEPAL CA-720(trademark), IGEPAL CO-890(trademark), IGEPAL CO-720(trademark), IGEPAL CO-290(trademark), IGEPAL CA-210(trademark), ANTAROX 890(trademark) and ANTAROX 897(trademark) in effective amounts of, for example, from about 0.1 to about 10 percent by weight of the reaction mixture; anionic surfactants such as, for example, sodium dodecylsulfate (SDS), sodium dodecylbenzene sulfonate, sodium tetrapropyl diphenyloxide disulfonate, sodium dodecyinaphthalene sulfate, dialkyl benzenealkyl sulfates and sulfonates, abitic acid, available from Aldrich, NEOGEN R(trademark), NEOGEN SC(trademark) obtained from Kao, DOWFAX 2A1(trademark) obtained from Dow, and the like, in effective amounts of, for example, from about 0.01 to about 10 percent by weight; ionic surfactants, and more specifically, cationic surfactants, such as, for example, dialkyl benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl ammonium bromide, benzalkonium chloride, cetyl pyridinium bromide, C12, C15, C17 trimethyl ammonium bromides, halide salts of quaternized polyoxyethylalkylamines, dodecylbenzyl triethyl ammonium chloride, MIRAPOL(trademark) and ALKAQUA(trademark) available from Alkaril Chemical Company, SANIZOL(trademark) (benzalkonium chloride), available from Kao Chemicals, and the like, in effective amounts of, for example, from about 0.01 percent to about 10 percent by weight. More specifically, the molar ratio of the cationic surfactant used for flocculation to the anionic surfactant used in the latex preparation is in the range of from about 0.5 to about 4.
Examples of surfactants, which may be added, such as to the aggregates before coalescence is initiated, include anionic surfactants, such as sodium dodecylbenzene sulfonate, sodium dodecylnaphthalene sulfate, dialkyl benzenealkyl, sulfates and sulfonates, abitic acid, available from Aldrich, NEOGEN R(trademark), NEOGEN SC(trademark) obtained from Kao, and the like. They can also be selected from nonionic surfactants, such as polyvinyl alcohol, polyacrylic acid, methalose, methyl cellulose, ethyl cellulose, propyl cellulose, hydroxy ethyl cellulose, carboxy methyl cellulose, polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, dialkylphenoxypoly(ethyleneoxy)ethanol, available from Rhone-Poulenac as IGEPAL CA-210(trademark), IGEPAL CA-520(trademark), IGEPAL CA-720(trademark), IGEPAL CO-890(trademark), IGEPAL CO-720(trademark), IGEPAL CO-290(trademark), IGEPAL CA-210(trademark), ANTAROX 890(trademark) and ANTAROX 897(trademark). An effective amount of the anionic or nonionic surfactant utilized in the coalescence to primarily stabilize the aggregate size against further growth with temperature is, for example, from about 0.01 to about 10 percent by weight, and more specifically from about 0.5 to about 5 percent by weight of monomers used to prepare the copolymer resin.
Surface additives that can be added to the toner compositions after washing or drying include, for example, metal salts, metal salts of fatty acids, colloidal silicas, mixtures thereof, and the like, which additives are usually present in an amount of from about 0.1 to about 2 weight percent, reference U.S. Pat. Nos. 3,590,000; 3,720,617; 3,655,374 and 3,983,045, and U.S. Pat. No. 6,190,815 and the applications recited therein, the disclosures of which are totally incorporated herein by reference. Preferred additives include zinc stearate and AEROSIL R972(copyright) available from Degussa in amounts of from about 0.1 to about 2 percent, which can be added during the aggregation process or blended into the formed toner product.
Developer compositions can be prepared by mixing the toners obtained with the processes of the present invention with known carrier particles, including coated carriers, such as steel, ferrites, and the like, reference U.S. Pat. Nos. 4,937,166 and 4,935,326, the disclosures of which are totally incorporated herein by reference, for example from about 2 percent toner concentration to about 8 percent toner concentration. Also, there can be selected as carrier particles, or components a core with a coating thereover of polymethylmethacrylate with a conductive component dispersed therein, such as a conductive carbon black.
Imaging methods are also envisioned with the toners of the present invention, reference for example a number of the patents mentioned herein, and U.S. Pat. No. 4,265,990, the disclosure of which is totally incorporated herein by reference.
The following Examples are being submitted to further illustrate various species of the present invention. These Examples are intended to be illustrative only and are not intended to limit the scope of the present invention.
Encapsulated Yellow Pigment Synthesis:
An encapsulated yellow pigment comprised of a yellow pigment core and a styrene/n-butyl acrylate/2-carboxyethyl acrylate terpolymer shell was synthesized by a semicontinuous, miniemulsion polymerization process. 1-Dodecanethiol, with a solubility in water of 3xc3x9710xe2x88x925 grams per liter of water at 25xc2x0 C., was used as a cosurfactant and as a primary chain transfer agent. In a 2 liter jacketed glass reactor with a stirrer set at 300 rpm, 5.3 grams of DOWFAX 2A1(trademark) (sodium tetrapropyl diphenyloxide disulfonate, 47 percent active, Dow Chemical), 1.9 grams of ANTAROX CA-897(trademark) (70 percent active, octylphenol aromatic ethoxylate, Rhone-Poulenc), and 756 grams of deionized water were deaerated for 30 minutes while the temperature was raised to 80xc2x0 C. A miniemulsion was prepared by homogenizing a monomer mixture (290 grams of styrene, 97 grams of n-butyl acrylate, 23.2 grams of 2-carboxyethyl acrylate, 1.9 grams of 2,2xe2x80x2-azobis(2-methylbutyronitrile), 15.5 grams of 1-dodecanethiol, and 33.5 grams of Yellow 17 pigment with an aqueous solution of 1.3 grams of DOWFAX 2A1(trademark), 0.4 gram of ANTAROX CA-897(trademark), 3.9 grams of ammonium persulfate, and 224 grams of deionized water via VirTishear Cyclone Homogenizer at 10,000 rpm for 30 minutes at room temperature, about 25xc2x0 C. throughout. The resulting miniemulsion was fed into the above reactor over a period of 105 minutes. At the conclusion of the monomer feed, the emulsion was post-heated at 80xc2x0 C. for 30 minutes, then there was added an initiator aqueous solution of 1.9 grams of ammonium persulfate and 20 grams of deionized water. After the above initiator addition was completed, the reaction was allowed to post react for 90 minutes at 80xc2x0 C., then cooled to 25xc2x0 C. The resulting encapsulated yellow pigment contained 28 percent solids comprised of poly(styrene-butyl acrylate-2-carboxyethyl acrylate) and Yellow Pigment 17, and possessed an average particle size of 395 nanometers as measured by light scattering technique on a Coulter N4 Plus Particle Sizer, and more specifically, the resulting product was comprised of about 92 percent of shell polymer of poly(styrene-butyl acrylate-2-carboxyethyl acrylate), and Yellow Pigment 17 core, about 8 percent by weight, wherein the polymer shell possessed an average thickness of about 85 nanometers, which was determined by transmission electron microscope image analysis of a thin section of the yellow pigment encapsulated latex. The shell polymer possessed an Mw of 29,000, an Mn of 6,200, both as determined on a Waters GPC, and a mid-point Tg of 52.6xc2x0 C., as measured on a Seiko DSC.
Encapsulated Cyan Pigment Synthesis:
An encapsulated cyan pigment comprised of a cyan pigment core and a styrene/n-butyl acrylate/2-carboxyethyl acrylate terpolymer shell was synthesized by a semicontinuous, miniemulsion polymerization process. 1-Dodecanethiol, with a solubility in water of 3xc3x9710xe2x88x925grams per liter of water at 25xc2x0 C., was used (1-dodecanethiol has a dual function as a cosurfactant for the miniemulsion and as a primary chain transfer agent for polymer molecular weight regulation). In a 2 liter jacketed glass reactor with a stirrer set at 300 rpm, 5.3 grams of DOWFAX 2A1(trademark) (sodium tetrapropyl diphenyloxide disulfonate, 47 percent active, Dow Chemical), 1.9 grams of ANTAROX CA-897(trademark) (70 percent active, octylphenol aromatic ethoxylate, Rhone-Poulenc), and 765 grams of deionized water were deaerated for 30 minutes while the temperature was raised to 80xc2x0 C. A miniemulsion was prepared by homogenizing a monomer mixture (303 grams of styrene, 101 grams of n-butyl acrylate, 24.3 grams of 2-carboxyethyl acrylate, 2 grams of 2,2xe2x80x2-azobis(2-methylbutyronitrile), 20.2 grams of 1-dodecanethiol, and 54.6 grams of cyan 15:3 pigment) with an aqueous solution (1.3 grams of DOWFAX 2A1(trademark), 0.4 gram of ANTAROX CA-897(trademark), 4.1 grams of ammonium persulfate, and 258 grams of deionized water) via VirTishear Cyclone Homogenizer at 10,000 rpm for 30 minutes at room temperature. The miniemulsion was fed into the reactor over 115 minutes. At the conclusion of the monomer feed, the emulsion was post-heated at 80xc2x0 C. for 30 minutes, then there was added an initiator aqueous solution (2 grams of ammonium persulfate and 20 grams of deionized water). After the above initiator addition was completed, the reaction was allowed to post react for 90 minutes at 80xc2x0 C., then cooled to 25xc2x0 C. The resulting encapsulated cyan pigment contained 28 percent solids comprised of poly(styrene-butyl acrylate-2-carboxyethyl acrylate) and cyan pigment 15:3, and possessed an average particle size of 343 nanometers as measured by light scattering technique on a Coulter N4 Plus Particle Sizer. The resulting encapsulated product was comprised of about 96.3 percent of polymer, poly(styrene-butyl acrylate-2-carboxyethyl acrylate), and a core of the cyan pigment 15:3, about 3.7 percent by weight, and more specifically, the resulting encapsulated product was comprised of a cyan pigment core and a poly(styrene-butyl acrylate-2-carboxyethyl acrylate) polymer shell, wherein the polymer shell possessed an average thickness of about 95 nanometers as determined by transmission electron microscope image analysis. The polymer possessed an Mw of 31,000, an Mn of 7,400, both as determined on a Waters GPC, and a mid-point Tg of 51.4xc2x0 C., as measured on a Seiko DSC.
Encapsulated Magenta Pigment Synthesis:
An encapsulated magenta pigment comprised of a magenta pigment core and a styrene/n-butyl acrylate/2-carboxyethyl acrylate terpolymer shell was synthesized by semicontinuous, miniemulsion polymerization process. 1-Dodecanethiol, with a solubility in water of 3xc3x9710xe2x88x925 grams per liter of water at 25xc2x0 C., was selected as the cosurfactant and as a primary chain transfer agent. In a 2 liter jacketed glass reactor with a stirrer set at 300 rpm, 5.3 grams of DOWFAX 2A1(trademark) (sodium tetrapropyl diphenyloxide disulfonate, 47 percent active, Dow Chemical), 1.9 grams of ANTAROX CA-89(trademark) (70 percent active, octylphenol aromatic ethoxylate, Rhone-Poulenc), and 656 grams of deionized water were deaerated for 30 minutes while the temperature was raised to 80xc2x0 C. A miniemulsion was prepared by homogenizing a monomer mixture (296 grams of styrene, 99 grams of n-butyl acrylate, 25 grams of 2-carboxyethyl acrylate, 2 grams of 2,2xe2x80x2-azobis(2-methylbutyronitrile), 9 grams of 1-dodecanethiol, and 25.2 grams of magenta 81.3 pigment) with an aqueous solution (1.3 grams of DOWFAX 2A1(trademark), 0.4 gram of ANTAROX CA-89(trademark), 4 grams of ammonium persulfate, and 224 grams of deionized water) via VirTishear Cyclone Homogenizer at 10,000 rpm for 30 minutes at room temperature. The miniemulsion was fed into the reactor over 180 minutes. At the conclusion of the monomer feed, the emulsion was post-heated at 80xc2x0 C. for 30 minutes, followed by the addition of an initiator aqueous solution of 1.9 grams of ammonium persulfate and 20 grams of deionized water. After the above initiator addition was completed, the reaction was allowed to post react for 90 minutes at 80xc2x0 C., then cooled to 25xc2x0 C. The resulting encapsulated magenta pigment contained 26 percent solids comprised of poly(styrene-butyl acrylate-2-carboxyethyl acrylate) and magenta pigment 81.3, and possessed an average particle size of 493 nanometers as measured by light scattering technique on a Coulter N4 Plus Particle Sizer, and more specifically, the resulting encapsulated product was comprised of about 95 percent of shell polymer, poly(styrene-butyl acrylate-2-carboxyethyl acrylate), and magenta pigment 81.3, about 5 percent by weight, wherein the polymer shell possessed an average thickness of about 80 nanometers, as determined by transmission electron microscope image analysis of a thin section of the magenta pigment encapsulated latex. The polymer possessed an Mw of 32,600, an Mn of 6,400, as determined on a Waters GPC, and a mid-point Tg of 50.9xc2x0 C., as measured on a Seiko DSC.
Encapsulated Black Pigment Synthesis:
An encapsulated black pigment comprised of a pigment core and a styrene/n-butyl acrylate/2-carboxyethyl acrylate terpolymer shell was synthesized by semicontinuous, miniemulsion polymerization process. 1-Dodecanethiol, with a solubility in water of 3xc3x9710xe2x88x925 grams per liter of water at 25xc2x0 C., was used as a cosurfactant and as a primary chain transfer agent. In a 2 liter jacketed glass reactor with a stirrer set at 300 rpm, 5.3 grams of DOWFAX 2A1(trademark) (sodium tetrapropyl diphenyloxide disulfonate, 47 percent active, Dow Chemical), 1.9 grams of ANTAROX CA-897(trademark) (70 percent active, octylphenol aromatic ethoxylate, Rhone-Poulenc), and 656 grams of deionized water were deaerated for 30 minutes while the temperature was raised to 80xc2x0 C. A miniemulsion was prepared by homogenizing a monomer mixture (296 grams of styrene, 99 grams of n-butyl acrylate, 24 grams of 2-carboxyethyl acrylate, 2 grams of 2,2xe2x80x2-azobis(2-methylbutyronitrile), 7 grams of 1-dodecanethiol, and 21.1 grams of REGAL 330(copyright) carbon black pigment) with an aqueous solution (1.3 grams of DOWFAX 2A1(trademark), 0.4 gram of ANTAROX CA-897(trademark), 4 grams of ammonium persulfate, and 227 grams of deionized water) via VirTishear Cyclone Homogenizer at 10,000 rpm for 30 minutes at room temperature. The miniemulsion was then fed into the reactor over 180 minutes. At the conclusion of the monomer feed, the emulsion was post-heated at 80xc2x0 C. for 30 minutes, then there was added an initiator aqueous solution of 1.9 grams of ammonium persulfate and 20 grams of deionized water. After the above initiator addition was completed, the reaction was allowed to post react for 90 minutes at 80xc2x0 C., then cooled to 25xc2x0 C. The resulting encapsulated black product contained 27 percent solids, which was comprised of a shell of poly(styrene-butyl acrylate-2-carboxyethyl acrylate) and REGAL 330(copyright) carbon black pigment, which product possessed an average particle size of 239 nanometers as measured by light scattering technique on a Coulter N4 Plus Particle Sizer, and more specifically, the resulting encapsulated product was comprised of about 95 percent of polymer, poly(styrene-butyl acrylate-2-carboxyethyl acrylate), and REGAL 330(copyright) carbon black pigment, about 5 percent by weight, wherein the polymer shell possessed an average thickness of about 65 nanometers, as determined by transmission electron microscope image analysis. The polymer possessed an Mw of 29,500, an Mn of 5,200, both as determined on a Waters GPC, and a mid-point Tg of 52.3xc2x0 C., as measured on a Seiko DSC.